If you suspect the endotracheal tube is in the right mainstem, what should you do?

• A. Advance the tube further into the right mainstem bronchus.
• B. Ignore unequal breath sounds and continue ventilation.
• C. Remove the tube and reattempt intubation immediately.
• D. Withdraw slightly or reposition and verify placement with capnography and auscultation.

Answer: (D)

When the tube is in the right mainstem bronchus, the goal is to bring it back to the midtrachea and confirm proper placement rather than leaving it deep or proceeding without verification. The tip sitting too far down the trachea splits ventilation, delivering most of the tidal volume to the right lung while the left lung is under-ventilated, which can cause left-sided atelectasis and overall poor oxygenation and ventilation.

The best action is to withdraw the tube slightly and reposition so the tip is about 2–3 cm above the carina in an adult, then verify placement with both capnography and auscultation. Capnography provides real-time confirmation that the tube lungs are being ventilated via a tracheal tube (a normal, consistent CO2 waveform). Auscultation helps ensure bilateral breath sounds and symmetric chest rise, indicating the tube is not preferentially ventilating only one lung. If the CO2 waveform is absent or diminished or breath sounds remain unequal despite repositioning, you should reassess and adjust further.

Why not advance the tube deeper, ignore the unequal sounds, or rush to reintubate without rechecking position first? Advancing would worsen mainstem intubation; ignoring asymmetry risks lung injury and poor ventilation; and reattempting intubation without confirming repositioning could waste time and miss the immediate corrective step. The combination of slight withdrawal, then verification with capnography and auscultation gives rapid, reliable confirmation of correct placement.